1. Field of the Invention
The present invention relates to a reciprocating compressor and particularly, to a reciprocating compressor, capable of enabling miniaturization of a compressor as a diameter of a compressor can be reduced and attenuating the installation space of the compressor.
2. Description of the Background Art
Generally, a compressor is an instrument for compressing fluid such as air and refrigerant gas and is classified into many kinds of compressors, such as a rotary compressor, reciprocating compressor, a scroll compressor and the like, according to the structure of the compressing method.
FIG. 1 is a longitudinal sectional view showing a reciprocating compressor in accordance with the conventional art, FIG. 2 is a longitudinal sectional view showing an arrangement structure of a spring of the reciprocating compressor in accordance with the conventional art and FIG. 3 is a cross-sectional view taken along section line IIIxe2x80x94III of FIG. 2.
The reciprocating compressor in accordance with the conventional art includes a hermetic casing 10 which is connected with a suction tube 12 to which gas is sucked and discharging tube 14, a driving motor 30 which is positioned inside the hermetic casing 10, for generating a reciprocating driving force, a compressing unit 40 for compressing gas moving reciprocatingly by receiving the driving force of the driving motor 30 and a plurality of frames which are fixed inside the hermetic casing, for supporting the driving motor 30 and compressing unit 40.
The driving motor 30 includes a cylindrical outer core 31, an inner core 32 which is positioned at a predetermined interval with the inner circumferential surface of the outer core 31, a winding coil 35 which is wound inside the outer core 31 and to which a power source is supplied from the outside, a magnet 33 which is positioned between the outer core 31 and inner core 32 at a predetermined interval and performs a linear reciprocating movement when the power source is supplied to the winding coil 35.
The compressing unit 40 includes a piston 42 which is connected with the magnet 33 by a magnet holder 34, a cylinder 41 in which the piston 42 is inserted slidably, for forming a predetermined compression space, and a valve assembly 44 positioned at the front of the cylinder 41, for performing opening and closing operations for the discharged gas.
Here, a first frame 21 is fixed on the outer circumferential surface of the cylinder 41 and the second and third frames 22 and 23 are supported on the both surfaces of the outer core 31.
The first frame 21 and second frame 22 are connected to each other by a connection member 24 and the second and third frames 22 and 23 are connected to each other by a bolt 61. The piston 42 is connected to the portion between the first and second frames 21 and 22, and a spring seat member 53 which performs a reciprocating movement together is positioned therein. A first spring 51 for giving an elastic force in the direction that the piston 42 moves backwards is positioned between a side surface of the first frame 21 and a side surface of the spring seat member 53, and a second spring 52 for giving an elastic force in the direction that the piston 42 moves forwards is positioned between the spring seat member 53 and second frame 22.
Here, the first spring 51 is mounted between an inner surface of a portion which is connected with the connection member 24 of the first frame 21 and a side surface of the spring seat member 53, stores an elastic force when the piston 42 moves forwards and gives the force when the piston 42 moves backwards. The second spring 52 is mounted between an another surface of a spring seat member 53 and a side surface of the second frame 22, stores an elastic force when the piston 42 moves forwards and gives the force when the piston 42 moves backwards.
Such reciprocating compressor has been gradually miniaturized and accordingly technology for miniaturizing the compressor maintaining an identical operation performance is required.
Therefore, the technology for miniaturizing the diameters of the first, second and third frames has become more influential, since the diameter of the hermetic casing is determined by the diameters of the first, second and third frames.
However, since the first and second springs are mounted on the inner surface of a part which is connected with the connection member of the first frame, diameter of each frame must be maintained larger than a predetermined level. Therefore, it is impossible to reduce the diameter, and accordingly the diameter of the compressor is larger than a predetermined level, thus to require larger installation space where the compressor is positioned and increase manufacturing cost of the compressor.
Therefore, an object of the present invention is to provide a reciprocating compressor, capable of reducing a diameter of a compressor by reducing diameters of frames, thus to miniaturize the compressor and substantially reduce the installation space of the compressor.
To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described herein, there is provided a reciprocating compressor, including a compressing unit fixed by a first frame inside a hermetic casing, for compressing gas, a driving motor fixed by a second frame and a third frame inside the hermetic casing, a spring seat member connected with a piston of the compressing unit and positioned between the first frame and the second frame, a plurality of connection members respectively connecting the first and second frame and having a predetermined space in the circumferential direction of the first and second frame, a first spring installed between the first frame and the spring seat member and a second spring installed between the spring seat member and the second frame, wherein each end of the first and second springs is positioned in a space among the connection members.
Further, there is provided a reciprocating compressor wherein the second and third frames are connected by a plurality of bolts and the bolts are inserted into a plurality of through holes circumferentially formed in a outer core of the driving motor.
The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.